The invention relates generally to turbine technology. More particularly, the invention relates to a nozzle including a duct member having substantially uniform wall thickness that replaces conventional airfoil nozzles for a turbine.
One goal of current turbine development is evaluating replacement of metal parts with composite matrix material (CMM) parts. During evaluation, usually a CMM part takes the place of one of the similarly structured metal parts, and the machine is tested. It is difficult, however, in some instances to replace a single metal part with a CMM part and operate the machine with both types of parts because the materials have fundamentally different physical characteristics, e.g., strength, elasticity, etc. In particular, use of the CMM part in some settings leads to machine failure. Another challenge is that evaluation of the applicability of a CMM part may require modification of the part, some times in place on a machine.
One turbine part that has been identified for evaluation for replacement by CMM parts are turbine nozzles or vanes, which are used to direct a gas flow to rotor buckets on a gas turbine. Each nozzle has an airfoil or blade shape configured such that when a set of the nozzles are positioned about a rotor of the turbine, they direct the gas flow in an optimal direction and with an optimal pressure against the rotor buckets. The metal nozzles have very specific physical characteristics in order to operate, and replacement of one metal nozzle with a CMM nozzle leads to machine failure. Consequently, meaningful evaluation of machine operation using a CMM nozzle in replacement of one metal nozzle in a set of metal nozzles is nearly impossible. Another challenge is that conventional nozzles are typically not readily accessible such that modifications can be easily made during evaluation, e.g., modification may require dismantling of the turbine and possibly removal of the nozzle.